Growth hormone increases the lipolytic sensitivity for catecholamines in adipocytes from healthy adults

The lipolytic effect of growth hormone (GH) was investigated in adipocytes obtained during elective surgery from otherwise healthy adults, 18-40 years old. No lipolytic or antilipolytic effect of GH was found when the cells were incubated with GH alone during 30min-6h. When the cells were preincubated with GH during 3h, the lipolytic sensitivity for isoprenaline increased markedly without any change in maximal lipolysis. However, a full effect was only obtained if GH was also present during the incubation with isoprenaline. GH did not alter DB-CAMP, enprophylline, or forskolin-induced lipolysis in human fat cells. In conclusion, GH had no direct lipolytic effect on human fat cells but GH markedly increased the catecholamine sensitivity. The site of the GH effect seems to be in the beta-adrenoceptors or in the Gs coupling protein.